The following example will terminate all instances of notepad.exe on an alert status of Down using PowerShell:

In the Trigger Action of the Advanced Alert, add a new action type of Execute an external program.

In the program to execute, type in "PowerShell" and the rest of the command line arguments, or the path to your PowerShell script.

Following is an example that terminates all running instances of notepad.exe. Note: You will need to enable impersonation through your PowerShell script or run the Advanced Alert Manager under a user account with elevated privileges.